In general a hybrid electric vehicle is a vehicle with a combination of a conventional/standard internal combustion propulsion system and an electric propulsion system. A hybrid electric vehicle utilizes the power generated from the internal combustion engine either to charge a battery of the vehicle or to provide driving force to the vehicle or combination of both.
Nowadays, the hybrid vehicle uses advanced technologies which improves the efficiency of the vehicle as well as reduces the emission as compared to conventional internal combustion propulsion system. One such technology is regenerative braking. In regenerative braking, the kinetic energy of the vehicle is converted into electric energy which may be stored in a battery or used to run electrical equipment of the vehicle.
The hybrid electric vehicle, in general, employs a conventional hydraulic brake system along with the advanced regenerative braking technology in order to generate desired braking force for the vehicle. However, such desired braking force is difficult to achieve by means of combined hydraulic and regenerative braking systems, such that the driver may feel unsecure with respect to the functional and capacity of the braking system. There is thus a need for an improved system for controlling regenerative braking in hybrid electric vehicle.